ever since my my first 'new' car, i try to adhere to 3000 miles. there is an audible difference in the way the engine runs when you first get in the car after an oil change. quieter, smoother. winters here especially, you can't exceed 3000. idling in traffic at below zero, you get some thick black tar you gotta get rid of.
i could see stretching it out to 4000 or so but the point is why? My engine will last longer on cleaner oil. sometimes by 3000 the oil on the dipstick is thick and black.
i've been rewarded by having cars not burn oil. i've maybe purchased a total of 8 quarts of oil for my cars between changes (that's 8 cars in 13 years). whenever i take them in for a change they are almost never down on the dipstick.
15,000 miles a year at 3,000 miles is 5 oil changes. 15,000 a year at 5,000 is 3 oil changes. that saves me maybe 50 bucks, but actually less because they always top off all my other fluids. excluding winter slush, i never need to buy wiper fluid. i save a little there.
my oil change at the ford dealer is where they caught my torn cv boot on my 500 and promptly had the appointment set up for the fix the next day. if you are still under warranty and they spot something, its pretty good preventive maintenance as well.